JP-A-11-255772 discloses phosphonocephem compounds having a superior antibacterial activity, wherein a lyophilized product of 7β-[2(Z)-ethoxyimino-2-(5-phosphonoamino-1,2,4-thiadiazol-3-yl)acetamido]-3-[4-(1-methyl-4-pyridinio)-2-thiazolylthio]-3-cephem-4-carboxylate represented by the formula: is described as one of the specific examples thereof.
In general, pharmaceutical agents are desired to be superior in quality such as absorbability, solubility, purity, stability, preservability, tractability and the like. Thus, the problem of the present invention is to provide an antibacterial agent (particularly anti-MRSA agent) having such quality as sufficiently satisfactory as a pharmaceutical product.